It's not necessarily fund-raising, but a few friends and I came up with this on a 14 hour bus ride last summer:
So, you know how most corps' (or I can infer by seeing people in halves) members where under armour, or a cheap rip-off there-of, underneath their unis? What if DCI would convince Under Armour to produce a drum corps line of shirts? For instance, Vanguard could have red, with the star on the left chest (pocket area; I don't know the correct term for that area of a shirt). They wear red under armour anyway, so it's not like its a big change.
Every corps could choose the colors and logo of their line, and the members could purchase them (possibly at discount) to wear under the unis. In addition, fans would be able to purchase them as another tribute to the corps. And of course, if someone was a real good negotiator, it might be possible to have a small fraction of the proceeds sent back to the corps of which the shirt represents.
Just a thought :)